There is a 3-4% healing difference between WAR and PLD.

This isn't 2.0. WAR isn't built around self healing anymore. WAR mitigates damage, consistently, no matter what. For every big hit they will always have at least 1 CD to use. That's their thing.

Here is what PLD has that WAR doesn't:

1.) A -STR down debuff
2.) A shield
3.) A silence
4.) Stoneskin
5.) Hallowed Ground
6.) Sword Oath

Here is what WAR has that PLD doesn't:

1.) -10% Slashing Resist
2.) -10% Damage Dealt
3.) Higher damage in tank stance
4.) AOE damage that isn't just a DoT
5.) A NON RNG Shield in the form of Inner Beast
6.) An off the GCD tank stance (meaning you can start tanking or stop tanking without using a GCD)

There's other stuff, but you get the point. Both are fine where they are. They compliment eachother and make up for what the other one lacks. WAR does its job perfectly fine, PLD does its job perfectly fine. The only thing I could see that needs changing on either is Holmgang, only because Hallowed Ground is just such a powerful CD and Holmgang really doesn't compare nor does it bring something that HG doesn't.

Also, tank DPS matters. The entire point of tank DPS and maximizing it is that you don't sacrifice your tanking capabilities for your DPS. If you need more health for that particular encounter, you don't just say "screw it!" and wear full STR accessories. You trade VIT for STR as needed. If you are compromising your group's DPS or your healer's DPS, then you aren't optimizing your DPS correctly. It's not only important in world first progression, it's important for getting the turn over as quick as possible and dealing with less mechanics. That, in itself, is a form of mitigation. So don't just think because you're a tank you can slack on DPS, that same argument can be made for healers not DPSing because their primary job is to heal. If you aren't dead, and they aren't doing anything else, they should be DPSing. You have NO excuse because tanking and DPSing go hand in hand (you're going to have to hit the boss to tank it).